Electric guitar design and construction vary greatly in the shape of the body and the configuration of the neck, bridge, and pickups. Guitars may have a fixed bridge or a spring-loaded hinged bridge that lets players "bend" the pitch of notes or chords up or down or perform vibrato effects. The sound of a guitar can be modified by new playing techniques such as string bending, tapping, hammering on, using audio feedback, or slide guitar playing. There are several types of electric guitar, including the solid-body guitar, various types of hollow-body guitars, the six-string guitar (the most common type, usually tuned E, A, D, G, B, E, from lowest to highest strings), the seven-string guitar, which typically adds a low B string below the low E, and the twelve-string electric guitar, which has six pairs of strings.

Many experiments at electrically amplifying the vibrations of a string instrument were made dating back to the early part of the 20th century. Patents from the 1910s show telephone transmitters were adapted and placed inside violins and banjos to amplify the sound. Hobbyists in the 1920s used carbon button microphones attached to the bridge; however, these detected vibration from the bridge on top of the instrument, resulting in a weak signal.[2] With numerous people experimenting with electrical instruments in the 1920s and early 1930s, there are many claimants to have been the first to invent an electric guitar.

The "Frying Pan", 1932

Electric guitars were originally designed by acoustic guitar makers and instrument manufacturers. Some of the earliest electric guitars adapted hollow-bodiedacoustic instruments and used tungsten pickups. The first electrically amplified guitar was designed in 1931 by George Beauchamp, the general manager of the National Guitar Corporation, with Paul Barth, who was vice president.[3] The maple body prototype for the one-piece cast aluminium"frying pan" was built by Harry Watson, factory superintendent of the National Guitar Corporation.[3] Commercial production began in late summer of 1932 by the Ro-Pat-In Corporation (Electro-Patent-Instrument Company), in Los Angeles,[4][5] a partnership of Beauchamp, Adolph Rickenbacker (originally Rickenbacher), and Paul Barth.[6] In 1934, the company was renamed the Rickenbacker Electro Stringed Instrument Company. In that year Beauchamp applied for a United States patent for an Electrical Stringed Musical Instrument and the patent was issued in 1937.[7][8][9][10]

By early-mid 1935, Electro String Instrument Corporation had achieved mainstream success with the A-22 Frying Pan, and set out to capture a new audience through its release of the "Electro-Spanish Model B" and the "Electro-Spanish Ken Roberts" which was the first full 25" scale electric guitar produced.[7][8][9][10] The Electro-Spanish Ken Roberts provided players a full 25" scale, with 17 frets free of the fretboard. It is estimated that fewer than 50 Electro-Spanish Ken Roberts were constructed between 1933 and 1937; fewer than 10 are known to survive today.[7][8][9][10]

The need for the amplified guitar became apparent during the big band era as orchestras increased in size, particularly when acoustic guitars had to compete with large, loud brass sections. The first electric guitars used in jazz were hollow archtop acoustic guitar bodies with electromagnetic transducers. Early electric guitar manufacturers include Rickenbacker in 1932; Dobro in 1933; National, AudioVox and Volu-tone in 1934; Vega, Epiphone (Electrophone and Electar), and Gibson in 1935 and many others by 1936.

The solid-body electric guitar is made of solid wood, without functionally resonating air spaces. The first solid-body Spanish standard guitar was offered by Vivi-Tone no later than 1934. This model featured a guitar-shaped body of a single sheet of plywood affixed to a wood frame. Another early, substantially solid Spanish electric guitar, called the Electro Spanish, was marketed by the Rickenbacker guitar company in 1935 and made of Bakelite. By 1936, the Slingerland company introduced a wooden solid-body electric model, the Slingerland Songster 401 (and a lap steel counterpart, the Songster 400).

The earliest documented performance with an electrically amplified guitar was in 1932, by Gage Brewer, a musician based in Wichita, Kansas.[2] He had an Electric Hawaiian A-25 (frypan, lap steel) and a standard Electric Spanish from George Beauchamp of Los Angeles. Brewer publicized his new instruments in an article in the Wichita Beacon of 2 October 1932 and through performances that month. The first recordings using the electric guitar were by Hawaiian-style players, in 1933. Bob Dunn of Milton Brown's Musical Brownies introduced the electric Hawaiian guitar to Western swing with his January 1935 Decca recordings, departing almost entirely from the Hawaiian musical influence and heading towards jazz and blues. Alvino Rey was an artist who took this instrument to a wide audience in a large orchestral setting and later developed the pedal steel guitar for Gibson. An early proponent of the electric Spanish guitar was jazz guitarist George Barnes, who used the instrument in two songs recorded in Chicago on 1 March 1938, "Sweetheart Land" and "It's a Low-Down Dirty Shame". Some incorrectly attribute the first recording to Eddie Durham, but his recording with the Kansas City Five was made 15 days later.[13] Durham introduced the instrument to a young Charlie Christian, who made the instrument famous in his brief life and would be a major influence on jazz guitarists for decades thereafter.[14]

Gibson's first production electric guitar, marketed in 1936, was the ES-150 model ("ES" for "Electric Spanish", and "150" reflecting the $150 price of the instrument, along with matching amplifier). The ES-150 guitar featured a single-coil, hexagonally shaped "bar" pickup, which was designed by Walt Fuller. It became known as the "Charlie Christian" pickup (named for the great jazz guitarist who was among the first to perform with the ES-150 guitar). The ES-150 achieved some popularity but suffered from unequal loudness across the six strings.

A functionally solid-body electric guitar was designed and built in 1940 by Les Paul from an Epiphone acoustic archtop. His "log guitar" (so called because it consisted of a simple 4x4 wood post with a neck attached to it and homemade pickups and hardware, with two detachable Epiphone hollow-body halves attached to the sides for appearance only) shares nothing in design or hardware with the solid-body Gibson Les Paul introduced in 1952. However, the feedback associated with hollow-bodied electric guitars was understood long before Paul's "log" was created in 1940; Gage Brewer's Ro-Pat-In of 1932 had a top so heavily reinforced that it essentially functioned as a solid-body instrument.[2] In 1945, Richard D. Bourgerie made an electric guitar pickup and amplifier for professional guitar player George Barnes. Bourgerie worked through World War II at Howard Radio Company, making electronic equipment for the American military. Barnes showed the result to Les Paul, who then arranged for Bourgerie to have one made for him.

This table shows the layout of pitches on a standard tuning six-string guitar, which is tuned E, A, D, G, B, E, going from the lowest-pitch, thickest string to the highest - pitch, thinnest string. The table depicts a guitar fretboard as it would appear to an observer looking at a guitar that is on its side and upside-down, thus giving the table the same appearance that a guitarist would see when holding the instrument in playing position. Zero is the nut; 5 is the fifth (tuning) fret. This table only shows up to the twelfth fret. Most electric guitars have additional frets beyond the twelfth fret which have the same layout as the 1st- 12th fret (although the notes are an octave higher in pitch).

Electric guitar design and construction vary greatly in the shape of the body and the configuration of the neck, bridge, and pickups. However, some features are present on most guitars. The photo below shows the different parts of an electric guitar. The headstock (1) contains the metal machine heads (1.1), which use a worm gear for tuning. The nut (1.4)—a thin fret-like strip of metal, plastic, graphite or bone—supports the strings at the headstock end of the instrument. The frets (2.3) are thin metal strips that stop the string at the correct pitch when the player pushes a string against the fingerboard. The truss rod (1.2) is a metal rod (usually adjustable) that counters the tension of the strings to keep the neck straight. Position markers (2.2) provide the player with a reference to the playing position on the fingerboard.[15]

The neck and fretboard (2.1) extend from the body. At the neck joint (2.4), the neck is either glued or bolted to the body. The body (3) is typically made of wood with a hard, polymerized finish. Strings vibrating in the magnetic field of the pickups (3.1, 3.2) produce an electric current in the pickup winding that passes through the tone and volume controls (3.8) to the output jack. Some guitars have piezo pickups, in addition to or instead of magnetic pickups.

Some guitars have a fixed bridge (3.4). Others have a spring-loaded hinged bridge called a vibrato bar, tremolo bar, or whammy bar, which lets players bend notes or chords up or down in pitch or perform a vibrato embellishment. A plastic pickguard on some guitars protects the body from scratches or covers the control cavity, which holds most of the wiring. The degree to which the choice of woods and other materials in the solid-guitar body (3) affects the sonic character of the amplified signal is disputed. Many believe it is highly significant, while others think the difference between woods is subtle. In acoustic and archtop guitars, wood choices more clearly affect tone.

Woods typically used in solid-body electric guitars include alder (brighter, but well rounded), swamp ash (similar to alder, but with more pronounced highs and lows), mahogany (dark, bassy, warm), poplar (similar to alder), and basswood (very neutral).[16] Maple, a very bright tonewood,[16] is also a popular body wood, but is very heavy. For this reason it is often placed as a "cap" on a guitar made primarily of another wood. Cheaper guitars are often made of cheaper woods, such as plywood, pine or agathis—not true hardwoods—which can affect durability and tone. Though most guitars are made of wood, any material may be used. Materials such as plastic, metal, and even cardboard have been used in some instruments.

The guitar output jack typically provides a monaural signal. Many guitars with active electronics use a jack with an extra contact normally used for stereo. These guitars use the extra contact to break the ground connection to the on-board battery to preserve battery life when the guitar is unplugged. These guitars require a mono plug to close the internal switch and connect the battery to ground. Standard guitar cables use a high-impedance 1/4-inch (6.35-mm) mono plug. These have a tip and sleeve configuration referred to as a TS phone connector. The voltage is usually around 1 to 9 millivolts.

A few guitars feature stereo output, such as Rickenbacker guitars equipped with Rick-O-Sound. There are a variety of ways the "stereo" effect may be implemented. Commonly, but not exclusively, stereo guitars route the neck and bridge pickups to separate output buses on the guitar. A stereo cable then routes each pickup to its own signal chain or amplifier. For these applications, the most popular connector is a high-impedance 1/4-inch plug with a tip, ring and sleeve configuration, also known as a TRS phone connector. Some studio instruments, notably certain Gibson Les Paul models, incorporate a low-impedance three-pin XLR connector for balanced audio. Many exotic arrangements and connectors exist that support features such as midi and hexaphonic pickups.

The bridge and tailpiece, while serving separate purposes, work closely together to affect playing style and tone. There are four basic types of bridge and tailpiece systems on electric guitars. Within these four types are many variants.

Pictured is a tremolo arm or vibrato tailpiece style bridge and tailpiece system, often called a whammy bar or trem. It uses a lever ("vibrato arm") attached to the bridge that can temporarily slacken or tighten the strings to alter the pitch. A player can use this to create a vibrato or a portamento effect. Early vibrato systems were often unreliable and made the guitar go out of tune easily. They also had a limited pitch range. Later Fender designs were better, but Fender held the patent on these, so other companies used older designs for many years.

Detail of a Squier-made Fender Stratocaster. Note the vibrato arm, the 3 single-coil pickups, the volume and tone knobs.

With expiration of the Fender patent on the Stratocaster-style vibrato, various improvements on this type of internal, multi-spring vibrato system are now available. Floyd Rose introduced one of the first improvements on the vibrato system in many years when, in the late 1970s, he experimented with "locking" nuts and bridges that prevent the guitar from losing tuning, even under heavy vibrato bar use.

Tune-o-matic with "strings through the body" construction (without stopbar)

The fourth type of system employs string-through body anchoring. The strings pass over the bridge saddles, then through holes through the top of the guitar body to the back. The strings are typically anchored in place at the back of the guitar by metal ferrules. Many believe this design improves a guitar's sustain and timbre. A few examples of string-through body guitars are the Fender Telecaster Thinline, the Fender Telecaster Deluxe, the B.C. Rich IT Warlock and Mockingbird, and the Schecter Omen 6 and 7 series.

Compared to an acoustic guitar, which has a hollow body, electric guitars make much less audible sound when their strings are plucked, so electric guitars are normally plugged into a guitar amplifier and speaker. When an electric guitar is played, string movement produces a signal by generating (i.e., inducing) a small electric current in the magnetic pickups, which are magnets wound with coils of very fine wire. The signal passes through the tone and volume circuits to the output jack, and through a cable to an amplifier.[19] The current induced is proportional to such factors as string density and the amount of movement over the pickups.

Pickups on a Fender Squier "Fat Strat" guitar—a "humbucker" pickup on the left and two single-coil pickups on the right.

Because in most cases it is desirable to isolate coil-wound pickups from the unintended sound of internal vibration of loose coil windings, a guitar's magnetic pickups are normally embedded or "potted" in wax, lacquer, or epoxy to prevent the pickup from producing a microphonic effect. Because of their natural inductive qualities, all magnetic pickups tend to pick up ambient, usually unwanted electromagnetic interference or EMI.[20] The resulting hum is particularly strong with single-coil pickups, and it is aggravated by the fact that many vintage guitars are insufficiently shielded against electromagnetic interference. The most common source is 50- or 60-Hz hum from power transmission systems (house wiring, etc.). Since nearly all amplifiers and audio equipment associated with electric guitars must be plugged in, it is a continuing technical challenge to reduce or eliminate unwanted hum.[21]

Double-coil or "humbucker" pickups were invented as a way to reduce or counter the unwanted ambient hum sounds (known as 60-cycle hum). Humbuckers have two coils of opposite magnetic and electric polarity to produce a differential signal. Electromagnetic noise that hits both coils equally tries to drive the pickup signal toward positive on one coil and toward negative on the other, which cancels out the noise. The two coils are wired in phase, so their signal adds together. This high combined inductance of the two coils leads to the richer, "fatter" tone associated with humbucking pickups.

Piezoelectric pickups use a "sandwich" of quartz crystal or other piezoelectric material, typically placed beneath the string saddles or nut. These devices respond to pressure changes from all vibration at these specific points.

Optical pickups are a type of pickup that sense string and body vibrations using infrared LED light. These pickups are not sensitive to EMI.

Some "hybrid" electric guitars are equipped with additional microphone, piezoelectric, optical, or other types of transducers to approximate an acoustic instrument tone and broaden the sonic palette of the instrument.

Electric guitar necks vary in composition and shape. The primary metric of guitar necks is the scale length, which is the vibrating length of the strings from nut to bridge. A typical Fender guitar uses a 25.5-inch scale length, while Gibson uses a 24.75-inch scale length in their Les Paul. While the scale length of the Les Paul is often described as 24.75 inches, it has varied through the years by as much as a half inch.[citation needed]

Frets are positioned proportionally to scale length—the shorter the scale length, the closer the fret spacing. Opinions vary regarding the effect of scale length on tone and feel. Popular opinion holds that longer scale length contributes to greater amplitude. Reports of playing feel are greatly complicated by the many factors involved in this perception. String gauge and design, neck construction and relief, guitar setup, playing style and other factors contribute to the subjective impression of playability or feel.

A bolt-on neck

Necks are described as bolt-on, set-in, or neck-through, depending on how they attach to the body. Set-in necks are glued to the body in the factory. They are said to have a warmer tone and greater sustain.[citation needed] This is the traditional type of joint. Leo Fender pioneered bolt-on necks on electric guitars to facilitate easy adjustment and replacement. Neck-through instruments extend the neck the length of the instrument, so that it forms the center of the body, and are known for long sustain and for being particularly sturdy.[citation needed] While a set-in neck can be carefully unglued by a skilled luthier, and a bolt-on neck can simply be unscrewed, a neck-through design is difficult or even impossible to repair, depending on the damage. Historically, the bolt-on style has been more popular for ease of installation and adjustment. Since bolt-on necks can be easily removed, there is an after-market in replacement bolt-on necks from companies such as Warmoth and Mighty Mite. Some instruments—notably most Gibson models—continue to use set-in glued necks. Neck-through bodies are somewhat more common in bass guitars.

Materials for necks are selected for dimensional stability and rigidity, and some allege that they influence tone. Hardwoods are preferred, with maple, mahogany, and ash topping the list. The neck and fingerboard can be made from different materials; for example, a guitar may have a maple neck with a rosewood or ebony fingerboard. In the 1970s, designers began to use exotic man-made materials such as aircraft-grade aluminum, carbon fiber, and ebonol. Makers known for these unusual materials include John Veleno, Travis Bean, Geoff Gould, and Alembic.

Aside from possible engineering advantages, some feel that in relation to the rising cost of rare tonewoods, man-made materials may be economically preferable and more ecologically sensitive. However, wood remains popular in production instruments, though sometimes in conjunction with new materials. Vigier guitars, for example, use a wooden neck reinforced by embedding a light, carbon fiber rod in place of the usual heavier steel bar or adjustable steel truss rod. After-market necks made entirely from carbon fiber fit existing bolt-on instruments. Few, if any, extensive formal investigations have been widely published that confirm or refute claims over the effects of different woods or materials on electric guitar sound.

A neck-through bass guitar

Several neck shapes appear on guitars, including shapes known as C necks, U necks, and V necks. These refer to the cross-sectional shape of the neck (especially near the nut). Several sizes of fret wire are available, with traditional players often preferring thin frets, and metal shredders liking thick frets. Thin frets are considered better for playing chords, while thick frets allow lead guitarists to bend notes with less effort.

An electric guitar with a folding neck called the "Foldaxe" was designed and built for Chet Atkins by Roger C. Field.[22]Steinberger guitars developed a line of exotic, carbon fiber instruments without headstocks, with tuning done on the bridge instead.

Fingerboards vary as much as necks. The fingerboard surface usually has a cross-sectional radius that is optimized to accommodate finger movement for different playing techniques. Fingerboard radius typically ranges from nearly flat (a very large radius) to radically arched (a small radius). The vintage Fender Telecaster, for example, has a typical small radius of approximately 7.25 inches. Some manufacturers have experimented with fret profile and material, fret layout, number of frets, and modifications of the fingerboard surface for various reasons. Some innovations were intended to improve playability by ergonomic means, such as Warmoth Guitars' compound radius fingerboard. Scalloped fingerboards added enhanced microtonality during fast legato runs. Fanned frets intend to provide each string with an optimal playing tension and enhanced musicality. Some guitars have no frets—and others, like the Gittler guitar, have no neck in the traditional sense.

While an acoustic guitar's sound depends largely on the vibration of the guitar's body and the air inside it, the sound of an electric guitar depends largely on the signal from the pickups. The signal can be "shaped" on its path to the amplifier via a range of effect devices or circuits that modify the tone and characteristics of the signal. Amplifiers and speakers also add coloration to the final sound.

Electric guitars usually have one to four magnetic pickups. Identical pickups produce different tones depending on how near they are to the neck or bridge. Bridge pickups produce a bright or trebly timbre, and neck pickups are warmer or more bassy. The type of pickup also affects tone. Dual-coil pickups sound warm, thick, perhaps even muddy; single-coil pickups sound clear, bright, perhaps even biting. Guitars don't require a uniform pickup type: a common mixture is the "fat Strat" arrangement of one dual-coil at the bridge position and single coils in the middle and neck positions, known as HSS (humbucker/single/single). Some guitars have piezoelectric pickup in addition to electromagnetic pickups. Piezo pickups produce a more acoustic sound. The piezo runs through a built-in equalizer (EQ) to improve similitude and control tone. A blend knob controls the mix between electromagnetic and piezoelectric sounds.

Where there is more than one pickup, a pickup selector switch is usually present. These typically select or combine the outputs of two or more pickups, so that two-pickup guitars have three-way switches, and three-pickup guitars have five-way switches (a Gibson Les Paul three-pickup Black Beauty has a three-position toggle switch which configures bridge, bridge and middle [switch in middle position] and neck pickups). Further circuitry sometimes combines pickups in different ways. For instance, phase switching places one pickup out of phase with the other(s), leading to a "honky", "nasal", or "funky" sound. Individual pickups can also have their timbre altered by switches, typically coil tap switches that effectively short-circuit some of a dual-coil pickup's windings to produce a tone similar to a single-coil pickup (usually done with push-pull volume knobs).

The final stages of on-board sound-shaping circuitry are the volume control (potentiometer) and tone control (which "rolls off" the treble frequencies). Where there are individual volume controls for different pickups, and where pickup signals can be combined, they would affect the timbre of the final sound by adjusting the balance between pickups from a straight 50:50.

The strings fitted to the guitar also have an influence on tone. Rock musicians often prefer the lightest gauge of roundwoundstring, which is easier to bend, while jazz musicians go for heavier, flatwound strings, which have a rich, dark sound. Steel, nickel, and cobalt are common string materials, and each gives a slightly different tone color. Recent guitar designs may incorporate much more complex circuitry than described above; see Digital and synthesizer guitars, below.

The solid-body electric guitar does not produce enough sound to be audible to the audience in a performance setting without it being plugged into an electronic amplifier (exceptions would be when a guitarist is doing a sound recording and plugs into the mixing console or when a bassist plugs directly into the PA system in a live show).

Guitar amplifiers are designed with a different approach than that used to design sound reinforcement systempower amplifiers and home "hi-fi" stereo systems. Audio amplifiers generally are intended to accurately reproduce the source signal without adding unwanted tonal coloration (i.e., they have a flat frequency response) or unwanted distortion. In contrast, most guitar amplifiers are intended to provide tonal coloration and/or overdrive (distortion of various types) that can add to a guitar signal. A common tonal coloration sought by guitarists is rolling off some of the high frequencies. Along with a guitarist's playing style and choice of electric guitar and pickups, the choice of guitar amp model is a key part of a guitarist's unique tone. Many top guitarists are associated with a specific brand of guitar amp. As well, electric guitarists in blues, rock and many related sub-genres often intentionally choose amplifiers or effects units with controls that distort or alter the sound (to a greater or lesser degree).

In the 1950s and 1960s, some guitarists began exploring a wider range of tonal effects by distorting the sound of the instrument. To do this, they used overdrive — increasing the gain of the preamplifier beyond the level where the signal could be reproduced with little distortion, resulting in a "fuzzy" sound. This effect is called "clipping" by sound engineers, because when viewed with an oscilloscope, the wave forms of a distorted signal appear to have had their peaks "clipped off", in the process introducing additional tones (often approximating the harmonics characteristic of a square wave of that basic frequency). This was not actually a new development in the musical instrument or its supporting gear, but rather a shift of aesthetics, such sounds not having been thought desirable previously. Some distortion modes with an electric guitar increase the sustain of single notes and chords, which changes the sound of the instrument. In particular, distortion made it more feasible to perform guitar solos that used long, sustained notes.

After distortion became popular amongst rock music groups, guitar amplifier manufacturers included various provisions for it as part of amplifier design, making amps easier to overdrive, and providing separate "dirty" and "clean" channels so that distortion could easily be switched on and off. The distortion characteristics of vacuum tube amplifiers are particularly sought-after in blues and many rock music genres, and various attempts have been made to emulate them without the disadvantages (e.g., fragility, low power, expense) of actual tubes. Distortion, especially in tube based amplifiers, can come from several sources: power supply sag as more power is demanded than the supply can provide at a steady voltage, deliberate gain over drive of active elements, or alterations in the feedback provisions for various circuit stages.[23]

Guitar amplifiers have long included at least a few effect units, often tone controls for bass and treble, an integrated tremolo system (sometimes incorrectly labeled (and marketed) as vibrato), and/or a mechanical spring reverb unit. In the 2010s, guitar amps often have onboard distortion effects. Some 2010-era amps provide multiple effects, such as chorus, flanger, phaser and octave down effects. The use of offboard effects such as stompbox pedals is made possible by either plugging the guitar into the external effect pedal and then plugging the effect pedal into the amp, or by using one or more effects loops, an arrangement that allows effects to be electrically or mechanically switched in or out of the signal path as desired. In the signal chain, the effects loop is typically located between the preamplifier stage and the power amplifier stages (though reverb units generally precede the effects loop if both are featured on an amplifier). This allows the guitarist to apply modulation effects to the signal after it has been processed through the preamplifier, something generally desirable, particularly with time-based effects such as delay. By the 2010s, guitar amplifiers usually included a distortion effect. Effects circuitry (whether internal to an amplifier or not) can be taken as far as amp modeling, by which is meant alteration of the electrical and audible behavior in such a way as to make an amp sound as though it were another (or one of several) amplifiers. When done well, a solid state amplifier can sound like a tube amplifier (even one with power supply sag), reducing the need to manage more than one amp. Some modeling systems even attempt to emulate the sound of different speakers/cabinets. Nearly all amp and speaker cabinet modeling is done digitally, using computer techniques (e.g., Digital Signal Processing or DSP circuitry and software). There is disagreement about whether this approach is musically satisfactory, and also whether this or that unit is more or less successful than another.[24][25]

In the 1960s, the tonal palette of the electric guitar was further modified by introducing effect units in its signal path, before the guitar amp, of which one of the earliest units was the fuzz pedal. Effects units come in several formats, the most common of which are the stompbox "pedal" and the rackmount unit. A stomp box (or pedal) is a small metal or plastic box containing the circuitry, which is placed on the floor in front of the musician and connected in line with the patch cord connected to the instrument. The box is typically controlled by one or more foot-pedal on-off switches and it typically contains only one or two effects. Pedals are smaller than rackmount effects and usually less expensive. "Guitar pedalboards" are used by musicians who use multiple stomp-boxes; these may be a DIY project made with plywood or a commercial stock or custom-made pedalboard.

A rackmount effects unit may contain an electronic circuit nearly identical to a stompbox-based effect, but it is mounted in a standard 19" equipment rack, which is usually mounted in a road case that is designed to protect the equipment during transport. More recently, as signal-processing technology continuously becomes more feature-dense, rack-mount effects units frequently contain several types of effects. They are typically controlled by knobs or switches on the front panel, and often by a MIDI digital control interface.

Typical effects include:

Effects such as stereo chorus, phasers and flangers, which shift the pitch of the signal by a small and varying amount, creating swirling, shimmering and whooshing noises

Effects such as octavers, which displace pitch by an exact musical interval

In the 1970s, as effects pedals proliferated, their sounds were combined with tube amp distortion at lower, more controlled volumes by using power attenuators, such as Tom Scholz's Power Soak, as well as re-amplified dummy loads, such as Eddie Van Halen's use of dummy-load power resistor, post-power-tube effects, and a final solid-state amp driving the guitar speakers.

Recent amplifiers may include digital technology similar to modern effects pedals, including the ability to model or emulate a variety of classic amps.

A multi-effects device (also called a "multi-FX" device) is a single electronics effects pedal or rack-mount device that contains many electronic effects. In the late 1990s and throughout the 2000s, multi-FX manufacturers such as Zoom and Korg produced devices that were increasingly feature-laden. Multi-FX devices combine several effects together, and most devices allow users to use preset combinations of effects, including distortion, chorus, reverb, compression, and so on. This allows musicians to have quick on-stage access to different effects combinations. Some multi-FX pedals contain modelled versions of well-known effects pedals or amplifiers.

Multi-effects devices have garnered a large share of the effects device market, because they offer the user such a large variety of effects in a single package. A low-priced multi-effects pedal may provide 20 or more effects for the price of a regular single-effect pedal. More expensive multi-effect pedals may include 40 or more effects, amplifier modelling, and the ability to combine effects and/or modelled amp sounds in different combinations, as if the user was using multiple guitar amps. More expensive multi-effects pedals may also include more input and output jacks (e.g., an auxiliary input or a "dry" output), MIDI inputs and outputs, and an expression pedal, which can control volume or modify effect parameters (e.g., the rate of the simulated rotary speaker effect).

By the 1980s and 1990s, software effects became capable of replicating the analog effects used in the past. These new digital effects attempt to model the sound produced by analog effects and tube amps, with varying degrees of quality. There are many free guitar effects computer programs that can be downloaded from the Internet. Now, computers with sound cards can be used as digital guitar effects processors. Although digital and software effects offer many advantages, many guitarists still use analog effects.

In 2002, Gibson announced the first digital guitar, which performs analog-to-digital conversion internally. The resulting digital signal is delivered over a standard Ethernet cable, eliminating cable-induced line noise. The guitar also provides independent signal processing for each individual string. In 2003, modelling amplifier maker Line 6 introduced the Variax guitar. It differs in some fundamental ways from conventional solid-body electrics. It has on-board electronics capable of modelling the sound of a variety of unique guitars and some other stringed instruments. At one time, some models featured piezoelectric pickups instead of the conventional electromagnetic pickups.

The sound of a guitar can not only be adapted by electronic sound effects but is also heavily affected by various new techniques developed or becoming possible in combination with electric amplification. This is called extended technique.

Extended techniques include:

String bending. This is not unique to the electric instrument, but it is greatly facilitated by the light strings typically used on solid-body guitars.

Neck bending, by holding the upper arm on the guitar body and bending the neck either to the front or pulling it back. This is used as a substitute for a tremolo bar, although not as effective, and the use of too much force could snap the guitar neck.

The use of the whammy bar or tremolo arm, including the extreme technique of dive bombing. The tremolo arm acts as a 'string shorten/tightener' which results in quick and effective pitch shifting. Instead of bending individual notes, this allows the entire guitar to sound lower or higher.

Tapping, in which both hands are applied to the fretboard. Tapping may be performed either one-handed or two-handed. It is an extended technique, executed by using one hand to tap the strings against the fingerboard, thus producing legato notes. Tapping usually incorporates pull-offs or hammer-ons as well, where the fingers of the left hand play a sequence of notes in synchronization with the tapping hand.

Pinch harmonics or artificial harmonics, sometimes called "squealies". This technique involves adding the edge of the thumb or the tip of the index finger on the picking hand to the regular picking action, resulting in a high-pitched sound.

Volume swell, in which the volume knob is repeatedly rolled to create a violin-like sound. The same result can also be accomplished through the use of an external swell pedal, although the knob technique can enhance showmanship and conveniently eliminate the need for another pedal.

Substitution of another device for the plectrum, for instance the cello bow (as famously used by Jimmy Page) and the e-bow, a device using electromagnetic feedback to vibrate strings without direct contact. Like feedback, these techniques increase sustain, bring out harmonics and change the acoustic envelope.

Use of a slide or bottleneck. The term slide refers to the motion of the slide against the strings, while bottleneck refers to the material originally used for such slides: the necks of glass bottles. Instead of altering the pitch of a string in the normal manner (by pressing the string against a fret), a slide is placed upon the string to vary its vibrating length and thus its pitch. The slide can be moved along the string without lifting, creating continuous transitions in pitch.

Unlike acoustic guitars, solid-body electric guitars have no vibrating soundboard to amplify string vibration. Instead, solid-body instruments depend on electric pickups and an amplifier (or amp) and speaker. The solid body ensures that the amplified sound reproduces the string vibration alone, thus avoiding the wolf tones and unwanted feedback associated with amplified acoustic guitars of the period. These guitars are generally made of hardwood covered with a hard polymer finish, often polyester or lacquer. In large production facilities, the wood is stored for three to six months in a wood-drying kiln before being cut to shape. Premium custom-built guitars are frequently made with much older, hand-selected wood.[citation needed]

One of the first solid-body guitars was invented by Les Paul. Gibson did not present their Gibson Les Paul guitar prototypes to the public, as they did not believe the solid-body style would catch on. Another early solid-body Spanish style guitar, resembling what would become Gibson's Les Paul guitar a decade later, was developed in 1941 by O.W. Appleton, of Nogales, Arizona.[27] Appleton made contact with both Gibson and Fender but was unable to sell the idea behind his "App" guitar to either company.[28] In 1946, Merle Travis commissioned steel guitar builder Paul Bigsby to build him a solid-body Spanish-style electric.[29] Bigsby delivered the guitar in 1948. The first mass-produced solid-body guitar was Fender Esquire and Fender Broadcaster (later to become the Fender Telecaster), first made in 1948, five years after Les Paul made his prototype. The Gibson Les Paul appeared soon after to compete with the Broadcaster.[30] Another notable solid-body design is the Fender Stratocaster, which was introduced in 1954 and became extremely popular among musicians in the 1960s and 1970s for its wide tonal capabilities and more comfortable ergonomics than other models.

Some solid-bodied guitars, such as the Gibson Les Paul Supreme, the PRS Singlecut, and the Fender Telecaster Thinline, among others, are built with hollows in the body. These hollows are designed specifically not to interfere with the critical bridge and string anchor point on the solid body. In the case of Gibson and PRS, these are called chambered bodies. The motivation for this may be to reduce weight, to achieve a semi-acoustic tone (see below) or both.[31][32][33]

Semi-acoustic guitars have a hollow body (similar in depth to a solid-body guitar) and electronic pickups mounted on the body. They work in a similar way to solid-body electric guitars except that, because the hollow body also vibrates, the pickups convert a combination of string and body vibration into an electrical signal. Whereas chambered guitars are made, like solid-body guitars, from a single block of wood, semi-acoustic and full-hollowbody guitars bodies are made from thin sheets of wood. They do not provide enough acoustic volume for live performance, but they can be used unplugged for quiet practice. Semi-acoustics are noted for being able to provide a sweet, plaintive, or funky tone. They are used in many genres, including blues, funk, sixties pop, and indie rock. They generally have cello-style F-shaped sound holes. These can be blocked off to prevent feedback, as in B. B. King's famous Lucille. Feedback can also be reduced by making them with a solid block in the middle of the soundbox.

Full hollow-body guitars have large, deep bodies made of glued-together sheets, or "plates", of wood. They can often be played at the same volume as an acoustic guitar and therefore can be used unplugged at intimate gigs. They qualify as electric guitars inasmuch as they have fitted pickups. Historically, archtop guitars with retrofitted pickups were among the very earliest electric guitars. The instrument originated during the Jazz Age, in the 1920s and 1930s, and are still considered the classic jazz guitar (nicknamed "jazzbox"). Like semi-acoustic guitars, they often have f-shaped sound holes.

Having humbucker pickups (sometimes just a neck pickup) and usually strung heavlly, jazzboxes are noted for their warm, rich tone. A variation with single-coil pickups, and sometimes with a Bigsby tremolo, has long been popular in country and rockabilly; it has a distinctly more twangy, biting tone than the classic jazzbox. The term archtop refers to a method of construction subtly different from the typical acoustic (or "folk" or "western" or "steel-string" guitar): the top is formed from a moderately thick (1 inch or 2–3 cm) piece of wood, which is then carved into a thin (0.1 in, or 2–3 mm) domed shape, whereas conventional acoustic guitars have a thin, flat top.

Some steel-string acoustic guitars are fitted with pickups purely as an alternative to using a separate microphone. They may also be fitted with a piezoelectric pickup under the bridge, attached to the bridge mounting plate, or with a low-mass microphone (usually a condenser mic) inside the body of the guitar that converts the vibrations in the body into electronic signals. Combinations of these types of pickups may be used, with an integral mixer/preamp/graphic equalizer. Such instruments are called electric acoustic guitars. They are regarded as acoustic guitars rather than electric guitars, because the pickups do not produce a signal directly from the vibration of the strings, but rather from the vibration of the guitar top or body.

Electric acoustic guitars should not be confused with semi-acoustic guitars, which have pickups of the type found on solid-body electric guitars, or solid-body hybrid guitars with piezoelectric pickups.

The four-string guitar is normally tuned CGDA, but some players, such as Tiny Grimes, tune to DGBE in order to preserve familiar 6-string guitar chord fingerings. The tenor guitar can also be tuned like a soprano, concert, or tenor ukulele, using versions of GCEA tuning.

Most seven-string guitars add a low B string below the low E. Both electric and classical guitars exist designed for this tuning. A high A string above the high E instead of the low B string is sometimes used. Another less common seven-string arrangement is a second G string situated beside the standard G string and tuned an octave higher, in the same manner as a twelve-stringed guitar (see below). Jazz guitarists using a seven-string include George Van Eps, Lenny Breau, Bucky Pizzarelli and his son John Pizzarelli.

Seven-string electric guitars were popularized among rock players in the 1980s by Steve Vai. Along with the Japanese guitar company Ibanez, Vai created the Universe series seven-string guitars in the 1980s, with a double locking tremolo system for a seven-string guitar. These models were based on Vai's six-string signature series, the Ibanez Jem. Seven-string guitars experienced a resurgence in popularity in the 2000s, championed by Deftones, Limp Bizkit, Slayer, KoRn, Fear Factory, Strapping Young Lad, Nevermore, Muse and other hard rock and metal bands. Metal musicians often prefer the seven-string guitar for its extended lower range. The seven-string guitar has also played an essential role in progressive metal rock and is commonly used in bands such as Dream Theater and Pain of Salvation and by experimental guitarists such as Ben Levin.

Eight-string electric guitars are rare but not unused. One is played by Charlie Hunter, which was manufactured by Novax Guitars. The largest manufacturer of eight- to 14-string instruments is Warr Guitars. Their models are used by Trey Gunn (ex King Crimson), who has his own signature line from the company. Similarly, Mårten Hagström and Fredrik Thordendal of Meshuggah used 8-string guitars made by Nevborn Guitars and now guitars by Ibanez. Munky of the nu metal band KoRn is also known to use seven-string Ibanez guitars, and it is rumored that he is planning to release a K8 eight-string guitar similar to his K7 seven-string guitar. Another Ibanez player is Tosin Abasi, lead guitarist of the progressive metal band Animals as Leaders, who uses an Ibanez RG2228 to mix bright chords with very heavy low riffs on the seventh and eighth strings. Stephen Carpenter of Deftones also switched from a seven-string to an eight-string in 2008 and released his signature STEF B-8 with ESP Guitars. In 2008, Ibanez released the Ibanez RG2228-GK, which is the first mass-produced eight-string guitar. Jethro Tull's first album uses a nine-string guitar. Bill Kelliher, guitarist for the heavy metal group Mastodon, worked with First Act on a custom mass-produced nine-string guitar.

B.C. Rich manufactures a ten-string six-course electric guitar, the Bich, whose radical shape positions the machine heads for the four secondary strings on the body, avoiding the head-heaviness of many electric twelve-string guitars. However many players bought it for the body shape or electrics and simply removed the extra strings. The company recognized this and released six-string models of the Bich, but ten-string models also remain in production.

Twelve-string electric guitars feature six pairs of strings, usually with each pair tuned to the same note. The extra E, A, D, and G strings add a note one octave above, and the extra B and E strings are in unison. The pairs of strings are played together as one, so the technique and tuning are the same as a conventional guitar, but they create a much fuller tone, with the additional strings adding a natural chorus effect. They are used almost solely to play harmony and rhythm parts, rather than for guitar solos. They are relatively common in folk rock music. Lead Belly is the folk artist most identified with the twelve-string guitar, usually acoustic with a pickup.

George Harrison of the Beatles and Roger McGuinn of the Byrds brought the electric twelve-string to notability in rock and roll. During the Beatles' first trip to the United States, in February 1964, Harrison received a new 360/12 model guitar from the Rickenbacker company, a twelve-string electric made to look onstage like a six-string. He began using the 360 in the studio on Lennon's "You Can't Do That" and other songs. McGuinn began using electric twelve-string guitars to create the jangly, ringing sound of the Byrds. Both Jimmy Page, the guitarist with Led Zeppelin, and Leo Kottke, a solo artist, are well known as twelve-string guitar players.

Popular music and rock groups often use the electric guitar in two roles: as a rhythm guitar which provides the chord sequence or "progression" and sets out the "beat" (as part of a rhythm section), and a lead guitar, which is used to perform melody lines, melodic instrumental fill passages, and guitar solos. In some rock or metal bands with two guitarists, the two performers may perform as a guitar tandem, and trade off the lead guitar and rhythm guitar roles. In bands with a single guitarist, the guitarist may switch between these two roles, playing chords to accompany the singer's lyrics, and then playing a guitar solo in the middle of the song.

In the most commercially available and consumed pop and rock genres, electric guitars tend to dominate their acoustic cousins in both the recording studio and live venues, especially in the "harder" genres such as heavy metal and hard rock. However the acoustic guitar remains a popular choice in country, western and especially bluegrass music, and it is widely used in folk music. Even metal and hard rock guitarists play acoustic guitars for some ballads and for MTV unplugged acoustic performances.

Jazz guitar playing styles include rhythm guitar-style "comping" (accompanying) with jazz chord voicings (and in some cases, walking basslines) and "blowing" (improvising solos) over jazz chord progressions with jazz-style phrasing and ornaments. The accompanying style for electric guitar in most jazz styles differs from the way chordal instruments accompany in many popular styles of music. In rock and pop, the rhythm guitarist usually performs the chords in dense and regular fashion, which sets out the beat of a tune. Rock and pop chord voicings tend to focus on the first, third, and fifth notes of the chord. In contrast, in many modern jazz styles, the guitarist plays much more sparsely, intermingling periodic chords and delicate voicings into pauses in the melody or solo. Jazz chord voicings are usually rootless and emphasize the third and seventh notes of the chord. Jazz chords also often include the 9th, 11th and 13th notes of the chord, which are called "extensions".

When jazz guitar players improvise, they use scales, modes, and arpeggios associated with the chords in a tune's chord progression. Jazz guitarists have to learn how to use scales (whole tone scale, chromatic scale, etc.) to solo over chord progressions. Jazz guitar improvising is not merely the recitation of jazz scales and rapid arpeggios. Jazz guitarists try to imbue their melodic phrasing with the sense of natural breathing and legato phrasing used by horn players such as saxophone players. As well, a jazz guitarists' solo improvisations have to have a rhythmic drive and "time feel" that creates a sense of "swing" and "groove". In addition to the traditional rhythm/comping and lead/blowing roles, some jazz guitarists use the electric instrument to play unaccompanied, combining harmony notes and the melody to form a complete piece of music, like classical guitarists.

Most jazz guitarists play hollow-body instruments, but solid-body guitars are also used. Hollow-body instruments were the first guitars used in jazz in the 1930s and 1940s. During the 1970s jazz fusion era, many jazz guitarists switched to the solid body guitars that dominated the rock world, using powerful guitar amps to get a loud sound.

In the 21st century, European avant garde composers like Richard Barrett, Fausto Romitelli, Peter Ablinger, Bernhard Lang, Claude Ledoux and Karlheinz Essl have used the electric guitar (together with extended playing techniques) in solo pieces or ensemble works. Probably the most ambitious and perhaps significant work to date is Ingwe (2003–2009) by Georges Lentz (written for Australian guitarist Zane Banks), a 60-minute work for solo electric guitar, exploring that composer's existential struggles and taking the instrument into realms previously unknown in a concert music setting.

In Vietnam, electric guitars are often used as an instrument in cải lương music (traditional southern Vietnamese folk opera), sometimes as a substitute for certain traditional stringed instruments like the Đàn nguyệt (two-stringed lute) when they are not available. Electric guitars used in cải lương are played in finger vibrato (string bending), with no amplifiers or sound effects.

^For more on this subject see Tomaro, Robert (1994). "Contemporary compositional techniques for the electric guitar in United States concert music". Journal of New Music Research. 23 (4): 349. doi:10.1080/09298219408570664.

ON! The Beginnings of Electric Sound Generation – an exhibit at the Museum of Making Music, National Association of Music Merchants, Carlsbad, CA – some of the earliest electric guitars and their history, from the collection of Lynn Wheelwright and others

King of Kays Vintage guitar's from America, Japan, and Italy. Pictures, history, and forums.